Satellite radio has been very successful, especially in the US with the Sirius XM radio, in which transmissions are made via dedicated satellites in S-Band.
S band is part of the microwave band of the electromagnetic spectrum, which extends to frequencies at the range of from 2 to 4 GHz.
In the US, the FCC approved satellite-based Digital Audio Radio Service (DARS) broadcasting in the S band at the sub range of from 2.31 to 2.36 GHz, which is currently used by Sirius XM radio. More recently, it has approved for portions of the S band between 2.0 and 2.2 GHz the creation of Mobile Satellite Service (MSS) networks in connection with Ancillary Terrestrial Components (ATC). There are presently a number of companies attempting to deploy such networks.
In some countries, S band is used for Direct-to-Home satellite television (unlike similar services in most countries, which use Ka band). The frequency typically allocated for this service is 2.5 to 2.7 GHz (LOF 1.570 GHz).
However, with the ever growing demand for the world's communication frequency bands, e.g. for cellular phones, streaming entertainment, data communications, civil and commercial providers, incredible strains are placed on available spectrum bandwidth. In the electromagnetic spectrum, many NASA missions use S-band for communications, therefore commercial businesses have put pressure on the US government to free up other bands within the electromagnetic spectrum.
Consequently, a new part of the electromagnetic spectrum called Ka-band has been opened and with the need to speed up transmissions, Ka-band, has been considered a promising spectrum for communications. Compared with S-band, Ka-band has data transmission rates that are hundreds of times faster and enables global coverage with local high gain spot beams.
The Ka band covers frequencies range of from about 26.5 to about 40 GHz, i.e. wavelengths from slightly over one centimeter down to 7.5 millimeters. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. The 30/20 GHz band is used in satellites communications, where the uplink transmissions are transmitted in either the 27.5 GHz and 31 GHz bands, and high-resolution, close-range targeting radars aboard military airplanes. Some frequencies in this radio band are used for vehicle speed detection by law enforcement.
The Ku band covers frequencies range of from about 12 to about 18 GHz portion of the electromagnetic spectrum in the microwave range of frequencies. The Ku band is primarily used for satellite communications, including the provisioning of fixed and broadcast services. Ku band satellites are also used for backhauls and particularly for satellite from remote locations back to a television network's studio for editing and broadcasting.
When considering the Ka band or Ku band, or even higher frequencies, as the media for transmissions for mobile terminals, one of the major problems is the problem of blockage. As known in the art, a blockage protection system based on very long interleaving and long period storage of the received signal, makes it possible to overcome blockage periods of several seconds. The satellite radio signal being a relatively low bandwidth signal with a very high latency tolerance, makes the solution feasible and cost-effective.
However, as in the case of Sirius XM radio, terrestrial augmentation would be required. Typically, such an augmentation could not rely on Ka-band transmissions as those provide only very short range coverage for a terrestrial link.